Protractor



(N oooo A No. 413,497. Patented Oct. Z2,I 1889. I

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i UNITED STATESl PATENT OFFICE.

CLARENCE E. DE PUY, OF JACKSON, MICHIGAN.

n PROT RACTO R.

SPECIFICATION forming part of Iletters Patent No. 413,497, dated October 22, `1889.

Application filed August 22, 1888. Serial No. 283,497. (No model.)

To @ZZ whom it may concern:

Beit known that I, CLARENE E, DE PUY, of Jackson, Michigan, have invented a new and useful Protractor, of which the following is a specification.

My invention relates to that class of protractors in which a movable semicircular ruler turns in a frame having at least one straight edge, the angle being read from a graduated scale on side of circular parts; and its object is to provide for'draftsmen a protraetor which can be easily adjusted to any angle and clamped, so that it will remain tlXed as long as desired, but with the adjusting and clamping screws so placed that the instrument can be used either side up without changing the adjustment or position of any of the parts. At the same time the instrument is light and convenient to handle. To accomplish this I prefer to make it of hard rubber, though it can be made of brass or other suitable material.

In the accompanying drawings, Figure l represents an outside view of the complete instrument; Fig. 2, a longitudinal section on line I I; Fig. 3, a cross-seetion on line II II; Fig. 4, a view ot the segment for making fine adjustments.

Similar letters of reference represent corresponding parts.

In the drawings, letter A represents a semicircular movable ruler B, a quadrilateralshaped frame holding said ruler, having a side X and an end X at right angles, the opposite end X2 at an angle 'ol' forty-live degrees, and the opposite side formedwith a semicircular depression corresponding to the semicireular side of A, and of sufficient depth to allow the straight side of A and the upper side of B not cutaway to form one straight line when said straight side of A and long side X of B are parallel. From the center of the circular side of A projects a tongue A', its thickness being onet`hi rd that of main partof A, into a slot B of sufficient length to all" low ruler A to turn through an angle of fortyive degrees.

The screw F, nut D, and washer E are for the purpose of clamping the ruler A in any desired position, and being placed in slot d, with F screwed into A', they move with said ruler as itis turned to make the various angles.

On the circular edge of rulerAare grooves au., of 'V or other suitable shape, which fit over corresponding elevations b b on B. The edges h2 h2 of the slot d are also beveled like b b', andt into corresponding angles e e in washer E in such a manner that the combination of the four beveled edges b b h2 b2 with the corresponding grooves a. a e the screw F and nut D so act when the nut D is tightened as to bring the parts A, A', B, and E into close contact. The tightening of nut D forces washer E against upper edge of slot d and also brings the circular edges of parts A and B together, but all the surfaces ot contact being beveled, as hereinbefore described, the bringing of these surfaces together produces a lateral pressure on parts h b, which forces them against the sides of A, thus preventing the springing ot' these otherwise thin parts and making a iirrn joint. The groove a, a and projection l1 h also serve to hold parts A and B in line sidewise when the nut D is loosened. The segment C, of some thin material, preferably steel, with the tangent screw IAI and nut Gr placed in annular openings I-I and G?, give a meansv of accurately adjusting ruler A to any desired angle. The circular edges of A and B are either or both (making a Vernier) graduated in anysuitable manner, so that the desired angle can be easily read from such graduated scale. The lower side of the projection A has a small portion C,corresponding to the width and thickness of segment C, cut away, thus allowing said segment to be placed in slot- ]3. The outside of segment C has the saine radius as upper side of slot d, thus allowing theml to coincide. The notch C is made slightly less in width than segment C, so that when nut D is tightened the washerE is first brought intopcontact with segment C, and that being in contact with the shoulderof C the segment C and semicircle A are firmly fastened, so that a longitudinal mdvement of C gives a corresponding circular motion to A. VThe central part of shoulder of notch .C' is eut slightly wider than at the outside, thus giving the space L, which allows segment C to spring slightly when nut D is further tightened after final adjustment by nut G has been made, thus allowing washer E to form irm contact with the parts, as hereinbefore described. The pin P passes through IOO the hole P in segment C and moves in slot I, which prevents excessive movement of segment C in either direction. j The annular depression J is formed to afford a convenient means of grasping nut G with the fingers.

The nuts D and G are made slightly less in diameter than the thickness of B, and being placed in the center of B they therefore do not project beyond the sides of said frame B, so that in using on the drawing-board the operator can use it either side up. This feature, in combination with the right angle of the frame, allows all possible angles to be obtained when theprotractor is used with an ordinary T-square, straight-edge, or on a line, although the movable ruler turns but forty- .five degrees.

The method of operation is this: When long side X rests on T-square, all angles from zero to forty-five degrees can be drawn, and when short side X rests on T-square all angles from forty-live degrees to ninety degrees can be drawn. So by using the instrument on either side of T-square all possible angles can be drawn.

I am aware that prior to my invention protractors have been made with a semicircular ruler moying in a quadrilateral frame, having both ends at right angles and the adjusting and clamping screws on one side; others having a blade with a circle at one end, which turns in a corresponding circular opening made in a holding-frame, but with no adjusting or clamping screws.

I therefore do not claim such constructions; but

What I do claim as my invention, and desire to secure by Letters Patent, is-

l. A protractor consisting of a frame with a part of a semicircular depression on one edge, a corresponding semicircular ruler turning in said depression, a projecting' tongue from one piece entering a corresponding slot in the other, and V-shaped grooves on edge of one of semicircular parts, one on each side of said tongue, itting over corresponding V- shaped elevations on edge of other semicircular part, for purposes substantially as set forth.

2. A protractor consisting of a frame with a part of a semicircular depression on one edge, a corresponding semicircular ruler turning in said depression, projecting tongue and V-shaped grooves on semicircular edge of one piece fitting corresponding slot and V-shaped elevations on semiciroular edge of the other, and a thumb nut and Washer with V-shaped channel placed in a slot cut through lside of protractor, s0.that said nut and Washer are entirely contained between the two surfaces of sides of protractor, and being for the purpose of clamping the semicircular ruler, substantially as set forth.

3. A protractor consisting of a frame with apart of a semicircular depression on one edge, a corresponding semicircular ruler turning in said depression, a projecting tongue and V-shaped grooves on edge of one piece fitting corresponding slot and V-shaped elevations on the other and arranged to be clamped with a thu mb-nut and V-shaped Washer, and a 'segment of a circle of some thin metal placed in same slot that receives the before-described projecting tongue, and which is also clamped to said tongue by the before-described thumbnut and V-shaped washer, said segment having on one end a tangent screw and thumbnut, by means of which accurate adjustments of semicircular ruler can be made in the manner hereinbefore described.

CLARENCE E. DE PUY. Witnesses:

K. B. MERRITT, E. R. LEWIS. 

